The clinical and histopathologic features of specific skin infiltrates in patients with B-cell chronic lymphocytic leukemia (B-CLL) have rarely been reported in detail. In this study we analyzed the clinical, histopathologic, immunophenotypic, and molecular features of 84 skin lesions from 42 patients (M:F = 1.3:1; mean age, 66.0 years; range, 42-83 years) with specific cutaneous manifestations of B-CLL. The duration of B-CLL before skin manifestations varied from 0 to 142 months (mean, 39 months). In seven patients (16.7%), skin lesions represented the first sign of disease. Clinical presentations included localized or generalized erythematous papules, plaques, nodules, and large tumors. Ulceration was uncommon. In six patients lesions were confined at the sites of scars from previous herpes zoster (four patients) or herpes simplex (two patients) eruptions. Histologically, three main patterns were recognized: (a) patchy perivascular and periadnexal, (b) nodular-diffuse, and (c) band-like. Cytomorphologically, small monomorphous lymphocytes predominated. Proliferation centers were observed in only four specimens. In two patients presenting with tumors, a high content of large cells with feature of centroblasts and immunoblasts was found (Richter's syndrome). Immunohistologic analyses were performed on paraffin-embedded specimens in 40 biopsies from 20 patients and on cryostat sections in 17 biopsies from 11 patients. Neoplastic B lymphocytes in all cases showed an aberrant phenotype (paraffin sections: CD20+/CD5+/CD43+; cryostat sections: CD19+/CD5+; immunoglobulin light-chain restriction). Proliferation markers (Ki67, PCNA, MIB1) stained 5 to 80% of cells (mean, 25%; median, 20%). Polymerase chain reaction performed in nine cases on paraffin-embedded tissues using consensus primers for immunoglobulin heavy-chain genes showed a monoclonal population of B lymphocytes in all cases. Several discrete bands in addition to the prominent ones were noted in five cases, indicating the additional presence of B lymphocytes whose immunoglobulin genes were not monoclonally but oligoclonally rearranged. Follow-up data could be obtained from 31 patients. The two patients with Richter's syndrome died after 5 and 8 months, respectively. The 5-year survival of patients with small-cell cutaneous B-CLL was 66.6%. Our study indicates that cutaneous specific manifestations of B-CLL present with characteristic histologic, immunophenotypic, and molecular patterns. Prognosis in these patients is probably not affected by skin involvement.

The study suggests a continuous spectrum of cutaneous myoepithelial neoplasms ranging from benign mixed tumor of the skin to cutaneous myoepithelioma and cutaneous myoepithelial carcinoma. Further studies with extended follow-up information are necessary to establish prognostic factors.

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We report the clinical, histopathologic, immunohistologic, and prognostic findings in 19 patients with cutaneous leiomyosarcoma, eight males and 11 females (mean age, 66 years; age range, 41-93 years). The tumors presented mainly as solitary lesions and were located on the head and neck (eight lesions), trunk (four lesions), upper extremities (three lesions), and lower extremities (four lesions). Histopathologically, two predominant growth patterns were observed: nodular (12 cases) and diffuse (seven cases). Neoplasms with a nodular growth pattern were characterized by high cellularity and prominent nuclear atypia, and they showed conspicuous mitoses, several necrotic cells, and sometimes extensive necrotic areas. By contrast, most cutaneous leiomyosarcomas with a diffuse growth pattern revealed low cellularity, well-differentiated smooth muscle cells, inconspicuous mitotic figures, and few or no necrotic cells. Immunohistologic investigations revealed all cutaneous leiomyosarcomas to express vimentin and smooth muscle actin. Pan-muscle actin (HHF-35) was also expressed in most cases (15 lesions). However, only 12 lesions showed positive staining for desmin. Remarkable was the expression of cytokeratins in five lesions. Clinical follow-up revealed local recurrences in five patients (three cases with nodular pattern and two lesions with a diffuse pattern) after a period ranging from 8 months to 3 years after surgical excision. No distant metastases have been observed in our series. We conclude that cutaneous leiomyosarcoma with a diffuse growth pattern may constitute a pitfall in histopathologic diagnosis because of the presence of only subtle criteria for malignancy. Cutaneous leiomyosarcoma may show different immunophenotypes, thus emphasizing the importance of using a large panel of antibodies (smooth muscle actin, HHF-35, desmin, vimentin, cytokeratins, and S-100 protein) in immunohistologic diagnosis. Cutaneous leiomyosarcoma sometimes reveals local recurrences, but it has negligible potential for distant metastases.

In 1983, Ackerman proposed that pilomatricoma represents an infundibular-matrix cyst in its early stages. To study the evolution of this cystic neoplasm, we examined 118 lesions from 116 patients with pilomatricoma histopathologically and categorized the lesions into four distinct and chronological stages: early, fully developed, early regressive, and late regressive. Early lesions (eight cases) were small cystic structures lined by squamoid and basaloid epithelium containing keratin filaments and faulty hair matrix material composed of shadow cells. Fully developed lesions (27 cases) were large neoplasms lined by basaloid epithelium at their periphery, and within, composed of irregularly shaped, densely packed zones of cornified masses containing shadow cells. Early regressive lesions (37 cases) had no apparent epithelial lining but did have basaloid cell foci at the periphery; within, they were composed of pink hair matrix material with shadow cells surrounded by granulation tissue with inflammatory infiltrate and multinucleated histiocytic giant cells. Late regressive lesions (42 cases) had no epithelial component and were composed of irregularly shaped, partially confluent masses of faulty hair material, and calcified (and sometimes metaplastically ossified) shadow cells embedded in a desmoplastic stroma, with little or no inflammatory infiltrate. In four cases, there was a relatively large dermal nodule composed of several interconnected lobules that consisted largely of basaloid cells with only a few areas of shadow cells. We interpreted these lesions as proliferating pilomatricomas. Based upon our histopathologic findings, we propose that pilomatricomas may be categorized into four distinct morphological stages and that these stages reflect the "life" of a pilomatricoma. Thus, the lesion begins as an infundibular matrix cyst and ends up as a calcified and ossified nodule with no visible epithelial component.